An X-Ray Crystallographic Study of <Emphasis Type=Italic>N</Emphasis>-Methyl-3-nitro-4-(nitromethyl)-4<Emphasis Type=Italic>H</Emphasis>-chromen-2-amine

Abstract  

4H-chromenes are among the essential groups of biologically important compounds used as synthetic ligands for drug designing and discovery process. In this study, we have presented the single-crystal structure analysis of racemic 4H-chromene derivative namely N-methyl-3-nitro-4-(nitromethyl)-4H-chromen-2-amine. The optical rotation measurement data is supporting that the title compound is racemic in nature. The compound was crystallized in monoclinic crystal system in the non-centrosymmetric space group P2₁ with unit cell parameters a = 5.1041 (3), b = 7.7519 (4), c = 14.7974 (8), α = 90°, β = 97.088 (5)° and γ = 90°. The nitro group of title compound is disordered over two orientations (N3A/O4A/O5A & N3B/O4B/O5B) with the refined site-occupancy ratio of 0.626(6)/0.374(6). The structure was solved by direct methods using the program SHELXS-97 and refined by SHELXL-97 with the full-matrix least square procedure to a final R-value of 0.0429 and Goodness of Fit (GooF) of 0.982. The molecules in the unit cell are stabilized by N–H···O and C–H···O types of hydrogen bonds. The intermolecular hydrogen bonds are forming C (6) motifs, which is observed to contribute the crystal packing stability. Moreover, the intramolecular hydrogen bonds are forming S (6) motif essential to stabilize the molecular structure of title compound.     

Synthesis and Crystal Structures of Methyl 3-(Benzoylamino)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-5-carboxylate and <Emphasis Type="Italic">N</Emphasis>-[5-(3,4-Dimethoxyphenyl)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-3-yl]benzamide

Abstract  

The compounds methyl 3-(benzoylamino)-6-methyl-2-oxo-2H-pyran-5-carboxylate (1), C₁₅H₁₃NO₅, and N-[5-(3,4-dimethoxyphenyl)-6-methyl-2-oxo-2H-pyran-3-yl]benzamide (2), C₂₁H₁₉NO₅, crystallize as a centrosymmetric hydrogen-bonded dimer facilitated by N–H···O interactions involving the amide and carbonyl moiety of the lactone group of adjacent molecules. Supramolecular aggregation in 1 is controlled by a combination of π–π interactions [centroid–centroid distance = 4.0745(11) ?] and weak C–H···O hydrogen bonding between the phenyl ring of the benzoylamino group and the carbonyl atom of the methoxycarbonyl group and in 2 by a combination of π–π interactions [centroid–centroid distance = 4.0699(8) and 4.1556(10) ?], weak C–H···O interactions between the methoxy substituents of the adjacent dimethoxyphenyl group and weak C–H··· π interactions.     

Synthesis and Crystal Structure of (5-Methyl-3-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-[5-(<Emphasis Type="Italic">p</Emphasis>-tolylamino)-2<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl]methanone

Abstract  

(5-Methyl-3-phenyl-1H-pyrazol-1-yl)-[5-(p-tolylamino)-2H-1,2,3-triazol-4-yl]methanone was synthesized and characterized by ¹H NMR, MS and IR spectra data. The structure of title compound was identified by X-ray diffraction. Compound, C₂₀H₁₈N₆O, Mr = 358.40, crystallizes in the triclinic space group P-1 with unit cell parameters a = 10.303(6), b = 12.489(7), c = 15.305(9) ?, α = 108.489(12), β = 101.920(11), γ = 96.971(13)°, V = 1790.0(17) ?³, Z = 4, Dx = 1.330 mg/cm³. The final R was 0.0520.     

Crystal Structure of <Emphasis Type=Italic>N</Emphasis>-(2-Pyridylmethylene)benzene-1,4-diamine

Abstract  

The crystal structure of amino containing Schiff base, N-(2-pyridylmethylene)benzene-1,4-diamine, was determined via X-ray diffraction analysis. The title compound crystallizes in orthorhombic system, space group Pc2 ₁ n, with unit cell dimensions a = 5.8945(6), b = 11.9233 (10), c = 14.5356 (16) ?, V = 1021.59 (18) ?³, Z = 4. The molecules are linked by intermolecular N–H···N hydrogen bonds to form supramolecular sheets along with the bc crystallographic plane. The crystal structure is further stabilized by C–H···π stacking interactions.     

Supramolecular organization of the crystal structure of <Emphasis Type=Italic>cis</Emphasis>-bis(thiosemicarbazide)palladium(II) <Emphasis Type=Italic>ortho</Emphasis>-hydrophthalate

This paper reports on the synthesis of a new palladium(II) thiosemicarbazide complex of the composition [Pd(HL)₂](HPht)₂ · 4H₂O(I) (where HL is N(1)H₂-N(2)H-C(3)(=S)-N(4)H₂ and HPht ⁻ is a monoanion of ortho-phthalic acid) and the results of an investigation of its structure. It has been demonstrated that two organic ligands are bidentately coordinated in the neutral form through a set of N and S donor atoms, which are located in the cis position with respect to the central metal atom. Three independent water molecules are joined by hydrogen bonds into the centrosymmetric associate {H₂O}₆. In the crystal, thiosemi-carbazide cationic complexes of palladium(II), monophthalate anions, and water molecules are self-organized into a supramolecular system with the formation of a three-dimensional structure based on ionic and hydrogen bonds.     

Synthesis and crystal structure of 2-anilino-6<Emphasis Type="Italic">H</Emphasis>-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine

A novel pyrazolone derivative 2-anilino-6H-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine (PMCP-PTSC) containing NNS hexa-atomic heterocycle has been obtained and characterized by means of single crystal X-ray diffraction, IR and ¹H NMR spectroscopies. It is interesting that when grown from two different solvents, two different crystalline structures are formed. The monoclinic crystal A belongs to a P2₁/c space group. The unit cell parameters are a = 16.414(4) Å, b = 12.530(3) Å, c = 8.432(1) Å, = 91.75(2) Å, and Z = 4. The triclinic crystal B belongs to a P space group. The unit cell parameters are a = 11.386(2) Å, b = 12.326(2) Å, c = 12.411(3) Å, = 83.07(1)°, = 87.76(2)°, = 86.52(2)°, and Z = 4. The structure analyses show the title compound is the keto-form. Dimers in crystal packing of A and supramolecular one-dimensional (B) concatenate structures were assembled by the intermolecular hydrogen bonds.     

Crystal Structure of 2-(2,2-Dibromovinyl)-1-methyl-1<Emphasis Type="Italic">H</Emphasis>-imidazole-4,5-dicarbonitrile

Abstract  

The crystal structure of 2-(2,2-dibromovinyl)-1-methyl-1H-imidazole-4,5-dicarbonitrile (C₈H₄Br₂N₄, Mr = 315.92) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with space group P2₁/c and unit cell parameters: a = 15.144(2), b = 16.382(3), c = 8.267(1) ?, β = 95.76(2)^o and Z = 8. The final reliability index is 0.0297 for 2505 observed reflections. The two molecules of 2-(2,2-dibromovinyl)-4,5-dicyano-1-methylimidazole are localized in independent part of unit cell. The crystal packing is stabilized by C–H···N hydrogen bonds and Br···N intermolecular interactions.     

Structure of <Emphasis Type=Italic>O</Emphasis>-Methyl-trinitrophloroglucinol Derivatives

Abstract  

The structures of mono, di, and tri-O-methyl derivatives of 2,4,6-trinitrophloroglucinol were determined by single crystal X-ray diffraction. As the number of methoxy groups increased from one to three the unit cell volume increased at a rate greater than the formula weight of the asymmetric unit such that crystal density decreased from 1.823 to 1.619 Mg/m³. The structural data reveal that the decreased density is related to increased angles between the plane of the phenyl ring and the planes defined by the nitro and methoxy groups, as well as fewer inter molecular interactions.     

X-ray crystallography of methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4<Emphasis Type="Italic">H</Emphasis>-pyran)-3-carboxylate

The organic carbonitrile namely methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4H-pyran)- 3-carboxylate is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst and its crystal structure is determined by X-ray technique. The crystals are monoclinic, sp. gr. C2/c, a = 12.3069(8) Å, b = 9.7023(7) Å, c = 24.812(2) Å, β = 94.862(6)°, Z = 8. The dihedral angle between pyran and phenyl rings is 87.8(1)°; the pyran ring is almost planar The dihedral angle between the mean planes of phenyl ring and nitro group is 44.4(2)°. The crystal structure is stabilized by N?H···N and N?H···O hydrogen bonds. In addition, C?H···π interactions are also observed in the crystal structure.     

Synthesis,Characterization, Crystal Structure,and Hirshfeld Surface Analysis of Ethyl 2-(4-bromophenyl)-1-cyclohexyl-1<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">d</Emphasis>]imidazole-5-carboxylate

The title compound, C₂₂H₂₃N₂BrO₂ was synthesized via one-pot reductive cyclization method and characterized by CNH analysis, FT-IR, UV-visible, mass, ¹H and ¹³C NMR spectra, thermogravimetric analysis (TGA) and single crystal X-ray diffraction method. The compound crystallizes in monoclinic crystal system: sp. gr. P2₁/c, Z = 4. The crystal data reveals that the intermolecular interactions of the C–H···π and π···π type connect the molecules which was also visualized with the help of Hirshfeld surface analysis.     

Crystal structure of (2<Emphasis Type="Italic">Z</Emphasis>)-(3,3-dimethyl-3,4-dihydroisoquinolin- 1(2<Emphasis Type="Italic">H</Emphasis>)-ylidene)nitrosoacetonitrile

The crystal structure of (2Z)-(3,3-dimethyl-3,4-dihydroisoquinolin-1(2Н)-ylidene)nitrosoacetonitrile is determined (T = 150 K, R1 = 0.0435). The compound crystallizes as the E-cis and Z-cis isomers of the nitroso tautomer. Two independent molecules differ in the rotation of the nitroso group about the С–С bond between the dihydroisoquinoline group and the substituent. Analysis of bond lengths reveals their conjugation and prevailing contribution of the zwitter-ionic structures with the positive charge located on the isoquinoline fragment and the negative charge located on the substituent. Molecules having E and Z conformations are connected by the N–H···O hydrogen bond (N···O 2.922(3) Å) into dimers. The N–H group of the other molecule forms the intramolecular N–H···O hydrogen bond (N···O 2.544(3) Å) which closes a sixmembered cycle. Electronic absorption spectra are studied, and quantum-chemical modeling of the compound is performed.